Devices and methods for analyzing rodent behavior

ABSTRACT

A device for detecting and recording animal behavior may include at least one corral that defines a contained field, the base surface of the at least one corral being sensitive to the animal&#39;s footprint. The device also includes an image capturing device that cooperates with the base surface to capture both a profile of the animal&#39;s full footprint and a profile of the animal&#39;s toe print when the animal is standing on its toes. In some embodiments, the device is capable of providing a stimulus to the animal and observing the resulting behavior of the animal via the image capturing device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority under 35 U.S.C§ 120 to U.S. application Ser. No. 15/032,730, filed Apr. 28, 2016,which is a national stage filing under 35 U.S.C. § 371 of InternationalApplication No. PCT/US2014/063400, entitled “DEVICES AND METHODS FORANALYZING RODENT BEHAVIOR and filed Oct. 31, 2014. InternationalApplication No. PCT/US2014/063400 claims the benefit under 35 U.S.C §119(e) of U.S. Provisional Application Ser. No. 61/898,754, entitled“DEVICES AND METHODS FOR ANALYZING RODENT BEHAVIOR,” filed Nov. 1, 2013.The entirety of each of the documents listed above is hereinincorporated by reference.

FEDERALLY SPONSORED RESEARCH

This invention was made with U.S. Government support under Grant Nos.DP2 OD007109, RO1 DC011558, and PO1NS072040, each awarded by theNational Institute of Health. The Government has certain rights in thisinvention.

FIELD

Devices and methods for analyzing rodent behavior are disclosed.

BACKGROUND

Rodent behavior detection and analysis may be a useful experimentaltool, for example, to determine whether a certain medication, stimulusor environment has a consequence on the animal's behavior. Suchinformation can be useful in developing treatments for use in otheranimals, including humans.

SUMMARY

Devices and methods for acquisition and analysis of animal behaviors aredisclosed. Aspects disclosed herein relate to devices and methods thatimage the inferior surfaces (e.g., the plantar surface of paws, andinferior body parts) of freely behaving laboratory rodents in lit ordark conditions. This enables the identification and analysis oflocomotion, gait, touch and pressure contact, nerve injury andregeneration, pain-like behavior, scratching, anxiety, aggression,social interaction, etc., of freely behaving rodents including mice andrats, either individually or in groups, and either in lit or darkenvironments. Conditions are observed via changes in the spatial extent,intensity and timing of the contact area of animal footpads and itsrelation to the rest of the body of the animal.

According to one aspect, a device for detecting and recording animalbehavior is disclosed. The device includes at least one corral defininga contained field. A base surface of the at least one corral issensitive to a footprint of the animal. An image capturing devicecooperates with the base surface to capture both a profile of a fullfootprint of the animal (e.g., extent and intensity) and a profile of atoe print of a freely-behaving animal when the animal is standing on itstoes, heels or footpads as well as by lighting the background orforeground to separately identify the position of the whole animal.

According to another aspect, a device for detecting and recording animalbehavior is disclosed. The device includes a transparent base surfacebeing sensitive to a footprint of the animal and an image capturingdevice beneath the base surface to capture both an image of a fullfootprint of the animal and an image of a toe print of the animal whenthe animal is standing on its toes. The device is adapted to provide astimulus to the animal (e.g., by targeting light at the point of contactwith the surface).

According to yet another aspect, a method of collecting behavioralinformation of a group of animals is disclosed. At least a subset of thegroup of animals is in a corral and is isolated from another subset ofthe group of animals. The method includes stimulating a first animalwith a stimulus and observing a resulting behavior of the first animalvia imaging both a footprint and a toe print of the first animal inresponse to the stimulus (e.g., imaging the spatial extent,pressure-related footprint intensity or timing of both the footprint andthe toe print of the first animal). In some embodiments, the stimulusmay include placing at least a subset of rodents in the same corral andobserving the social interactions amongst the subset of rodents.

It should be appreciated that the foregoing concepts, and additionalconcepts discussed below, may be arranged in any suitable combination,as the present disclosure is not limited in this respect. Further, otheradvantages and novel features of the present disclosure will becomeapparent from the following detailed description of various non-limitingembodiments when considered in conjunction with the accompanyingfigures.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a perspective view of a device for monitoring animal behavioraccording to one embodiment;

FIG. 2 is a perspective view of a device for monitoring animal behavioraccording to one embodiment;

FIG. 3 is a cross-sectional side view of a base surface of a device formonitoring animal behavior according to one embodiment;

FIG. 4 is a graph showing a physical activity of mice in corrals lit bywhite light and by non-visible near infrared light;

FIG. 5 is a cross-sectional side view of a device for monitoring animalbehavior according to another embodiment;

FIGS. 6A-6J are images representing screen shots of recordings capturedby a capturing device according to various embodiments, each showing arodent making contact with a base surface;

FIG. 7A-7B are images representing screen shots of recordings capturedby a capturing device according to other embodiments, each showing arodent making contact with a base surface;

FIG. 8 are images representing screen shots of recordings captured by acapturing device according to another embodiment, each showing a rodentmaking contact with a base surface; and

FIG. 9 is a schematic view of a computer system according to oneembodiment.

DETAILED DESCRIPTION

Valuable information can be learned for laboratory studies by monitoringand analyzing the activity and motor performance of animals, e.g.rodents. One such application is the identification and analysis oflocomotion, gait, touch and pressure against surfaces, nerve injury andregeneration, pain-like behavior, itch-like behavior, anxiety,aggression, and/or social interaction of the rodents. For example,identifying characteristic changes in gait that may accompany reactionsto certain stimuli. Applicants have recognized that by monitoring theactivity of freely behaving rodents, either individually or in groups,advantages may be realized. In some embodiments, the behavior of rodentsis monitored after the rodents have been genetically modified and/orafter the rodents are subjected to different types of stimulus in lit ordark environments.

According to one aspect, the voluntary and evoked movement of freelybehaving animals, such as rodents, e.g., mice or rats, is monitored viaa device capable of producing images of topographic featuresrepresenting an inferior surface of the freely behaving animal. In someembodiments, this includes the spatial extent, intensity and dynamicchanges of the surface. The inferior surface of the rodents may includea paw print, a toe print, or any other suitable inferior surface of theanimal, e.g., a rodents' abdomen or tail. Without wishing to be bound bytheory, freely behaving animals may include animals that are allowed totravel without obstruction within an area, such as a corral. It shouldbe noted that such corral is not limited to an outdoor area for largeanimals; rather, as contemplated herein, a corral can be a test chamberfor use with small animals, such as rodents (e.g., mice or rats).

In some embodiments, the device utilizes a horizontal contact sensorpositioned above a capturing device, such as a video camera. In someembodiments, the contact sensor is a horizontal, transparent sensor.During experimentation, the subject animal may be contained within anopen-bottom chamber and placed directly on top of the sensor, thuspermitting the animal to roam freely on top of the sensor while beingvideo recorded from below.

The sensor may be constructed based on the phenomenon of frustratedtotal internal reflection (FTIR) of band light. In some embodiments, thesensor is constructed based on FTIR of a non-visible band light, such asnear-infrared, infrared, or ultraviolet light, although other suitableband light may be employed as this aspect of the disclosure is notlimited in this regard. In one embodiment, the contact sensor includes ahorizontally-positioned transparent glass or acrylic panel with a lightsource in the non-visible range. For example, infrared LED lights may bepositioned around the perimeter of the panel (e.g., as strip lights oras lights mounted in a channel of a removable rail). Without wishing tobe bound by theory, when the light strikes the medium boundary betweenthe glass panel and the ambient air above the panel at an angle largerthan the critical angle, the light is totally internally reflected andno light is emitted towards the camera below. Again, without wishing tobe bound by theory, when an object, such as a mouse paw pad, having ahigher refractive index than air comes within several wavelengthsdistance of the glass/air boundary, the evanescent wave passes lightenergy into the object, making it visible to the camera below. Statedanother way, when the object, e.g. the mouse paw, comes into contactwith the panel, the internally reflected light is “frustrated” andrefracted out of the glass panel where it can be detected by a camerapositioned below the glass panel. In some embodiments, the intensity,contact area, spatial extent and position of the “frustrated” lightsignal and its change over time facilitates determining the physical andphysiological aspects of the animal's behavior, such as the relativeweight borne on each paw or the distribution of weight within eachfootprint. This, in turn, may provide an objective readout relating tothe subjective experience of the animal.

In some embodiments, the non-visible band light facilitates monitoringof nocturnal behavior during the nighttime period when rodents are mostactive. Without wishing to be bound by theory, as the light is notvisible to the animals, the animals are undisturbed, unless subjected toa stimulus, and thus are left to roam freely.

To facilitate observation of nocturnal behavior, the open-bottomedchamber may be made of an opaque material and the chamber areailluminated from a light source positioned under the panel or sensorusing red, near-infrared or other lighting that is not visible torodents. Similarly, a visible light source positioned beneath the sensoror panel may be used to illuminate the inferior surfaces of the animalthat are not in contact with the sensor.

In other embodiments, the device is configured to deliver differenttypes of stimulus to the freely roaming rodents and to examine therodents' behavioral responses after application of the stimulus. In someembodiments, the stimulus includes thermal, mechanical, electric, audio,olfactory or smell, textural, or light stimulation, although other typesof stimulation may be employed. In some embodiments, the stimulus isdelivered via the sensor, although the stimulus may be delivered viaother methods as this aspect of the disclosure is not limiting. Askilled artisan should appreciate that more than one stimulus (whethersimultaneous or sequential) may be applied to a single animal during thecourse of an experiment. A person having skill in the art should furtherappreciate that different stimuli may be applied to each of the animalsin a study when multiple animals are being tested.

In some embodiments, light stimulus may be delivered through the surfaceof the panel or sensor. For purposes herein, light stimulus may includethe application of light to stimulate a genetically engineered, lightsensitive animal and the application of light as a visual stimulus forany animal. For example, light stimulus may be applied by directingspecific wavelengths of laser generated light at points on the animalbody (e.g., the footpads) using a scanning mirror galvanometer or otherlaser pointing devices, or via LED arrays positioned below the sensorand generating specific light wavelengths directed through the sensor tothe entire inferior surface of the animal body. Light stimulus also maybe applied via LED arrays generating specific wavelengths of light thatcan be positioned to generate FTIR of light that is then delivered tothe surfaces of the rodent body in contact or nearby the sensor. Withoutwishing to be bound by theory, delivery of light using these methods maypermit control of specific peripheral nerve activity or cell functionusing light as stimulus while simultaneously imaging the mouse toacquire and analyze behavior data related to the light-activated nerveor cell activity. For example, light stimulus can be used for themanipulation of genetically encoded light-sensitive proteins to studyfunction of molecules, synapses, cells and system or other lightsensitive molecules engineered to interact or bind to cellular proteins.Also as an example, the expression of naturally occurring light-gatedproteins (e.g., channelrhodopsins) or the introduction of lightsensitive molecules in defined subsets of cells or proteins can addressimportant questions about cells and systems into which they areintroduced since they allow cellular activity, such as the activation ofspecific cell types or the opening of specific ion channels, to beperformed in a targeted manner by the administration of light. Also, achemical that binds to proteins and makes them light sensitive may beused. The applied light may be applied in different temporal patterns,different sizes and intensities for different durations in order toactivate or inhibit specific neurons, proteins or receptors.

In some embodiments, the surface temperature of the sensor may bemanipulated to explore behavioral responses to a thermal stimulus. Insome embodiments, the glass or panel may have a thermally conductivelayer or a thermally conductive plate may be used. The temperature alsomay be varied via an infrared heat source or via an infrared lightsource. In some embodiments, the temperature may be manually adjustedwhereas in other embodiments it may be automatically adjustable. In someembodiments, the surface upon which the animal is freely roaming mayhave one or more textures to stimulate the animal.

Turning now to the figures, FIG. 1 shows a device 100 for monitoringanimal behavior according to one embodiment. In some embodiments,monitoring animal behavior via the device 100 includes detecting andrecording animal behavior. The device 100 includes a corral 102 defininga contained field within which a rodent 104 may be housed during astudy. As shown in this figure, the corral 102 is an open field whichallows the rodent 104 to freely move. Although only one corral 102 isshown in the device 100 of FIG. 1, the device 100 may have multiplecorrals 102 in other embodiments. For example, as shown in FIG. 2, thedevice 100 may have two corrals 102 a, 102 b, each of which is shown tohouse a rodent 104 during a laboratory experiment. A person having skillin the art should appreciate that device 100 may have more than twocorrals 102 a, 102 b in other embodiments, as this aspect of thedisclosure is not limited in this regard. For example, the device 100may have 6, 8, 10, 12, or even 20 corrals in other embodiments. Askilled artisan also should appreciate that although only one rodent 104is shown in each of the corrals illustrated in FIGS. 1 and 2, the device100 may conduct experiments with more than one rodent 104 per corral.For example, depending on the size of the corral 102 and on theexperiment being conducted, each corral 102 may house 2, 4, 6, 8 or morerodents 104. A person having skill in the art should appreciate thateach corral need not house the same number of rodents. For example, inone embodiment, a first corral 102 a may house one rodent 104, while thesecond corral 102 b may house more than one rodent 104. Without wishingto be bound by theory, by having a device configured to allow multiplerodents 104 to be housed in the same corral, and to monitor the behaviorof each of the freely moving rodents 104, experiments relating to thesocial interactions, e.g., social anxiety, of the rodents 104 may beconducted.

Each corral 102 in the device 100 may be used to conduct separateexperiments. Additionally, although the device 100 may conduct the sameexperiment in all of the corrals 102, in some embodiments, the device100 may conduct different experiments in each corral 102. The device 100also may be configured such that all the corrals 102 begin theexperiment at the same time, although the device 100 may be configuredsuch that the experiment being performed in each corral 102 begins at adifferent time. This may improve consistency in the testing, e.g., byallowing all the experiments to begin after the same amount of time haspassed after each rodent has been genetically modified or stimulatedinstead of starting the experiments after different periods of time havepassed.

In some embodiments, additional “dummy” corrals that are identical tothe corrals 102 shown in FIGS. 1 and 2 are used to allow a first mouse(or group of mice) to be habituated to the test conditions while asecond mouse (or group of mice) is being tested in the corrals 102.

Although the corrals 102 in FIGS. 1 and 2 are shown having a transparentupper enclosure 106, thus allowing observation of the rodents 104 fromabove the device, a person having skill in the art should appreciatethat all or portions of the upper enclosure 106 also may be opaque. Insome embodiments, the upper enclosure 106 includes black walls thatprevent observation and light penetration via the top and sides of theupper enclosure 106.

As shown in FIG. 1, the device also includes a base surface 108 on whichthe rodents move and which is sensitive to the rodent's 104 paw print,toe print, or other inferior surface of the rodent. As shown in FIG. 1,the base surface 108 may be a transparent surface which allowsobservation of the rodent from below the device 100. For purposesherein, a transparent/clear surface may include a surface capable ofallowing visible and/or non-visible light to pass therethrough. In someembodiments, the base surface 108 is the sensor of the device 100.

As shown in FIG. 3, the base surface 108 includes an upper base surface110 and a lower base surface 112. In some embodiments, the base surface108 is a glass, acrylic, or silicone material, although other suitablematerials may be used as this aspect of the disclosure is not limited inthis regard. In some embodiments, all or portions of the upper basesurface 110 includes a textured surface which acts as a stimulus for therodent(s) 104 in the corral 102.

As shown in FIGS. 1-3, lights 114, such as LEDs, are positioned aroundthe perimeter of the base surface 108. In some embodiments, the lights114 are mounted in a channel (not shown) within a movable rail. In suchembodiments, the lights 114 and base structure 108 (e.g., a glass FTIRsurface) may be easily separated for replacement of broken parts and toallow for optimal positioning of lights relative to an edge of thesurface 108. In other embodiments, the lights 114 may be positioned asstrip lights around the edge of the surface 108.

The lights 114 emit light which may include a non-visible band light,e.g. near-infrared, infrared, or ultraviolet light, or another suitabletype of light. As shown in FIG. 3, the light emitted by the lights 114is totally internally reflected (see e.g. at 116). When a rodent's 104footprint, toe print, or other inferior surface comes into contact withthe upper base surface 110, e.g. at 118, the internally reflected lightbecomes frustrated and is refracted out of the base surface 108 via thebottom base surface 112.

The device 100 also may include a light source beneath the sensor orpanel to facilitate illumination of the inferior surfaces of the animalnot in contact with the sensor. This lighting may be positioned beneaththe sensor or panel in a location outside the perimeter of the chamberfootprint to facilitate lighting of the subject animal within thechamber while keeping the light source or reflections thereof away fromthe view of a camera or imaging device, e.g., a capturing device 120.

In some embodiments, rodents (e.g., mice) are more active when thecorral 102 is illuminated with a red or infrared lights, which are notvisible to the rodents, than when the corral 102 is illuminated with awhite light (e.g., a visible light). In such embodiments, the mice alsomay act more naturally when the corral is illuminated with red orinfrared light. Without wishing to be bound by theory, mice arenaturally active only when it is dark and remain dormant when it islight. Again, without wishing to be bound by theory, when mice areforced into a brightly illuminated space they show signs of stress. Itwas hypothesized that mice would become more active and behave morenaturally when confined to a corral with little to no visible light,instead of a conventional brightly lit corral, and in one embodiment, itwas observed that mice in a dark corral are active for a longer periodof time than mice in a lit environment.

For example, as illustrated in the graph in FIG. 4, when mice wereobserved for twenty (20) minutes in a translucent FTIR corral 102illuminated from all sides with white light, the mice were physicallyactive (e.g., walking, rearing, and grooming) for 13.41 minutes. Incontrast, when the mice were placed in an opaque (e.g., “blackout”)corral and were illuminated from below with only non-visible nearinfrared (NIR) light, the mice were physically active 19.39 of the 20minutes.

While lighting the animal from beneath may inform a detection algorithmof the relative positions of the head and tail of the animal, this addedlight also may reduce the dynamic range of the FTIR signal. In someembodiments, to maintain the full dynamic range of the FTIR signal, theunder lighting may be turned on only on alternating or for intermittentvideo frames. In such embodiments, this illumination strategy may permitrecording of separable data streams of the same animal behavior from onecapturing device 120 (e.g., a video camera), with one data stream beingused for dynamic range of FTIR-generated foot position data and theother being used for orientation and analysis of body position.

In some embodiments, for automated scoring of video data, the field ofview beyond the subject (e.g., rodent) is configured to be uniform incolor and light intensity. To optimize the data, a lightingconfiguration may be used that permits a freely behaving animal to beuniformly illuminated without generating any visible light orreflections of light in the field of view beyond the animal from theviewpoint of the capturing device. As shown in FIG. 5, the capturingdevice 120 (e.g., a camera) is positioned below a transparent basesurface 108 of the corral 102 and an opaque divider 130 is positionedbetween the corral 102 and the capturing device 120. The divider 130 mayhave a cutout that permits full view of the corral base surface 108 fromthe capturing device 120, while the field of view beyond the corral 102is occluded. In some embodiments, the surface finish of the opaquedivider 130 is matte to minimize secondary reflections. Lights 114 maybe positioned so that the capturing device 120 is shadowed from rays oflight 132 reflected off of lower base surface 112 of the corral basesurface 108. To prevent illumination of the interior surfaces of thecorral 102 from the viewpoint of the capturing device 120, the corralwalls and ceiling (collectively, 134) may be constructed from an opaquematerial with a reflective surface and may be positioned so thatreflected light rays 136 exiting the corral 102 are reflected away fromthe aperture of the capturing device 120.

As shown in FIG. 3, the capturing device 120 of the device 100 may belocated below the lower base surface 112 for capturing the refractedlight. In some embodiments, the capturing device 120 may be located inthe housing 122 (see FIG. 1) of the device, although, in otherembodiment the capturing device 120 may be separate from the device 100.The capturing device 120 may cooperate with the base surface 108 tocapture a profile of the rodent's 104 full footprint, toe print when therodent 104 is standing on its toes, or other inferior surface (e.g., therodent's 104 abdomen).

Examples of recordings captured by an exemplary capturing device can beseen in FIG. 6A-6J, which represent screen shots of the recordings takenby a video camera. FIG. 6A shows a Naïve mouse according to oneembodiment. FIG. 6B shows the mouse of FIG. 6A twenty-four hours after anerve injury. FIG. 6C shows the mouse of FIG. 6A twenty-one days afterthe nerve injury. FIG. 6D shows a Naïve rat according to anotherembodiment. FIG. 6E shows the rat of FIG. 6D twenty-four hours after anadjuvant-evoked injury to the rat's left hind paw. FIG. 6F illustrateshow rats show increasing footprint irradiance upon habituation in aninfrared-FTIR device enclosure. As shown in FIG. 6F, “tiptoeing”behavior often returns when an individual enters the room or upon loudnoise such as clapping (e.g., handclapping). FIG. 6G illustrates a ratwith no habituation. FIG. 6H shows the rat of FIG. 6G aftertwenty-minutes have passed. FIG. 6I illustrates FTIR in dark andunderlit conditions. FIG. 6J shows spontaneous injuries that aredetected in a Naïve mouse. These images reveal that rodents in a morerelaxed state exhibit more full-foot contact as opposed to rodents in amore anxious state that exhibit substantially toe-only contact.

FIGS. 7A and 7B illustrate examples of FTIR recordings showing distinctpain-related behaviors in mouse models of abdominal pain and distinctpain-related behaviors when a mouse paw is injured, respectively. Asshown in FIG. 7A at left, naïve mice walk with their weight shiftedtowards their hindpaws, which results in increased FTIR luminance of thehindpaws in this figure. In FIG. 7A at right, an embodiment showingabdominal pain, the mice shift their weight to their forepaws whilewalking. In such an embodiment, there is increased FTIR luminance of theforepaws as compared to that of the naïve mice shown in FIG. 7A at left.

FIG. 7B at left shows a naïve mouse standing on its hindpaws whilegrooming. In this embodiment, the luminance of each hind paw issubstantially similar. When a mouse has been injured in a spontaneousfight with another mouse, for example, the location of injury isindicated by different FTIR luminance for each hind paw. As shown inFIG. 7B, at right, the mouse has an fight-related injury to its righthind leg above the knee joint, which causes a reduced FTIR luminance inthe paw nearest the injured limb. Stated differently, in suchembodiments, mice with a spontaneous leg injury shift their weight tothe uninjured leg (which has a greater FTIR luminance).

FIG. 8 illustrates examples of FTIR recordings that detect analgesicefficacy, with great sensitivity. FIG. 8 at left shows a mouse after anexperimental induction of inflammation, and presumably pain, in its lefthind paw. FIG. 8 at right shows a mouse that has underwent the sameexperimental induction of inflammatory pain in the left hind paw as themouse in FIG. 8 at left, but has also been given an analgesic (e.g.,diclofenac) before FTIR imaging. As shown in these embodiments, themouse treated with the analgesic does not shift its weight to theuninjured leg like the mouse that was not treated with the analgesic.

FIG. 8 also demonstrates the capability of the device to detect not onlythe form of the contact areas of the paw, but also the relativepressures exerted within the contact areas of the paws (e.g., by showingthe differences in light intensity). For example, the FTIR images arebrighter in areas where there is greater relative pressure exerted bythe hind paw than in areas where there is less relative pressureexerted.

In some embodiment, the capturing device 120 is a camera for recordingthe movement of the rodent or rodents. The camera may be a near-infraredcamera in some embodiments, although other types of cameras may beemployed as this aspect of the disclosure is not limiting. Withoutwishing to be bound by theory, the type of capturing device 120corresponds to the type of band light emitted by the lights 114. Forexample, in embodiments in which a near-infrared band light is emittedby the lights 114, a near-infrared camera is used.

In some embodiments, the device 100 is configured such that images ofthe topographical features representing the inferior surface of eachfreely roaming rodent or rodents 104 in a single corral 102 may beseparately analyzed. Without wishing to be bound by theory, the behaviorof the rodent(s) 104 may be compared with either or both the behavior ofother rodent(s) 104 in the same corral 102 and the behavior of anyrodent(s) in other corrals 102.

As shown in FIG. 1, the device 100 also may have a control panel 124,such as a touch screen control panel, for controlling various parametersof the device 100, e.g. the stimulus applied in the corral 102. In someembodiments, the device 100 is connected to one or more control devices126, which may be used to control the device 100. The control device 126may be a computer (desktop or laptop), a tablet, a mobile device, or anyother suitable apparatus for controlling the device 100. As shown inFIG. 1, the device 100 may be directly connected 128 a to the controldevice 126 (e.g., via a USB connection) or the device 100 may beindirectly connected 128 b to the control device 126. The indirectconnection 128 b may include an internet, intranet, wireless, or othernetwork connection suitable for indirectly connecting the control device126 to the device 100. The control device 126 may run an applicationconfigured to store the images collected by the capturing device 120 andto process the images and/or convert the images into another data formatfor analysis. Other processing and/or analysis also may be performed bythe device 100 itself and/or by the control device 126.

The control device 126 in accordance with the techniques describedherein may take any suitable form, as aspects of the present inventionare not limited in this respect. An illustrative implementation of acomputer system 400 that may be used in connection with some embodimentsof the present invention is shown in FIG. 9. One or more computersystems such as computer system 400 may be used to implement any of thefunctionality described above. The computer system 400 may include oneor more processors 410 (e.g., processing circuits) and one or morecomputer-readable storage media (i.e., tangible, non-transitorycomputer-readable media), e.g., volatile storage 420 (e.g., memory) andone or more non-volatile storage media 430, which may be formed of anysuitable non-volatile data storage media. The processor(s) 410 maycontrol writing data to and reading data from the volatile storage 420and/or the non-volatile storage device 430 in any suitable manner, asaspects of the present invention are not limited in this respect. Toperform any of the functionality described herein, processor(s) 410 mayexecute one or more instructions stored in one or more computer-readablestorage media (e.g., volatile storage 420), which may serve as tangible,non-transitory computer-readable media storing instructions forexecution by the processor 410.

The above-described embodiments of the present invention can beimplemented in any of numerous ways. For example, the embodiments may beimplemented using hardware, software or a combination thereof. Whenimplemented in software, the software code (e.g., instructions) can beexecuted on any suitable processor or collection of processors, whetherprovided in a single computer or distributed among multiple computers.It should be appreciated that any component or collection of componentsthat perform the functions described above can be generically consideredas one or more controllers that control the above-discussed functions.The one or more controllers can be implemented in numerous ways, such aswith dedicated hardware, or with general purpose hardware (e.g., one ormore processors) that is programmed using microcode or software toperform the functions recited above.

In this respect, it should be appreciated that one implementation ofembodiments of the present invention comprises at least onecomputer-readable storage medium (i.e., at least one tangible,non-transitory computer-readable medium, e.g., a computer memory, afloppy disk, a compact disk, a magnetic tape, or other tangible,non-transitory computer-readable medium) encoded with a computer program(i.e., a plurality of instructions), which, when executed on one or moreprocessors, performs above-discussed functions of embodiments of thepresent invention. The computer-readable storage medium can betransportable such that the program stored thereon can be loaded ontoany computer resource to implement aspects of the present inventiondiscussed herein. In addition, it should be appreciated that thereference to a computer program which, when executed, performsabove-discussed functions, is not limited to an application programrunning on a host computer. Rather, the term “computer program” is usedherein in a generic sense to reference any type of computer code (e.g.,software or microcode) that can be employed to program one or moreprocessors to implement above-discussed aspects of the presentinvention.

In using the device 100, in one exemplary embodiment, at least a subsetof a group of rodents is obtained and placed in one or more corrals 102of the device 100. For purposes herein, a subset of rodents may includeone or more rodents. In some embodiments, a first subset of rodents isplaced in the corral 102 and isolated from another subset of rodents. Insome embodiments, the rodents are genetically modified prior toplacement in the corral 102. For example, the rodent may beoptogenetically modified for manipulation of genetically encodedlight-sensitive proteins to study the function of molecules, synapses,cells, and systems. There also may be proteins or other molecules givento the rodent. The device 100 may be enabled, either before or when therodents are placed in the corral 102 such that the lights 114 emit bandlight which is totally internally reflected within the base surface 108.

Next, a stimulus may be applied to the rodents. In some embodiments, alight stimulus is applied by delivering a light through the base. Thelight stimulus may include different wavelengths of light and/ordifferent patterns of light. In another embodiment, a thermal stimulusmay be applied. For example, the base surface 108 maybe heated or cooledand/or the entire corral may be heated or cooled. In other embodiments,the rodents are subjected to pain stimulus. In some embodiments, therodents 104 are subjected to different levels and types noises. Therodents also may be exposed to different smells. In some embodiments,multiple rodents are placed in the same corral to observe socialinteractions between the rodents. The applied stimulus may be deliveredthrough the base surface 108 in some embodiments, although, in otherembodiments, the stimulus may be delivered through alternate methods.

For devices performing a study using multiple rodents (whether in thesame corral or in different corrals), the rodents may be stimulated withthe same stimulus or with different stimuli. Additionally, the animalsmay receive only one stimulus or several different stimuli. The device100 also may be configured such that the rodents are tested for shortperiods of time and/or for extended periods of time.

The behavior of the rodents, both before and after the stimulus, may beobserved by imaging the spatial extent and intensity of signal of thefootprint, toe print, and/or other inferior surface of the animal inresponse to the stimulus and its change over time. For example, in someembodiments, the rodents may get anxious and stand up on their toescreating a distinctive footprint, which differs from the more flattenedfootprint created when the rodents have settled down. The image isgenerated as a result of contact between the footprint or toe print, orother inferior surface of the rodent, and the base surface 108, whichfrustrates the band light and causes the light to be reflected and toexit the base surface 108 for detecting by the capturing device 120. Thecapturing device 120 captures the illuminated areas on the base surface108 and these images are collected and analyzed.

While the present teachings have been described in conjunction withvarious embodiments and examples, it is not intended that the presentteachings be limited to such embodiments or examples. On the contrary,the present teachings encompass various alternatives, modifications, andequivalents, as will be appreciated by those of skill in the art.Accordingly, the foregoing description and drawings are by way ofexample only.

What is claimed is:
 1. A method of detecting and recording behavioralinformation of a group of animals in a corral, the method comprising:emitting band lights into a base surface of the corral via a pluralityof lights positioned around the base surface, the band lights beingtotally internally reflected within the base surface, the base surfacebeing sensitive to a footprint of one or more animals in the corral suchthat contact between the footprint of the one or more animals frustratesthe totally internally reflected light and refracts the light out of thebase surface; and capturing an image of both a full footprint of a firstanimal and an image of a toe print of the first animal when the firstanimal is standing on its toes.
 2. The method of claim 1, whereincapturing the image includes detecting refracted light when the firstanimal contacts the base surface.
 3. The method of claim 2, whereincapturing includes detecting refracted light resulting from contactbetween a foot and a toe of the first animal and the base surface. 4.The method of claim 1, wherein capturing the image includes capturingthe image of both the full footprint of the first animal and the imageof the toe print of the first animal via an image capture device.
 5. Themethod of claim 4, wherein capturing the image includes capturing theimage via the image capture device positioned beneath the base surface.6. The method of claim 1, wherein capturing includes capturing a spatialextent and intensity of a profile of the full footprint of the firstanimal and a profile of the toe print of the first animal and capturinga change of the profiles over time.
 7. The method of claim 1, furthercomprising capturing an image of the whole first animal independent ofsurface contact between the first animal and the base surface inconditions that mimic day or night.
 8. The method of claim 1, whereinemitting band lights includes emitting non-visible band lights into thebase surface.
 9. The method of claim 1, further comprising: stimulatingthe first animal with a first stimulus; and observing a resultingbehavior of the first animal via imaging both the footprint and the toeprint of the first animal in response to the first stimulus.
 10. Themethod of claim 9, wherein stimulating includes stimulating the firstanimal via at least one of a light stimulus, a temperature stimulus, ora texture stimulus.
 11. The method of claim 10, wherein stimulating thefirst animal includes stimulating the first animal via the base surface.12. The method of claim 11, wherein stimulating the first animal via thebase surface includes delivering light through the base surface.
 13. Themethod of claim 12, wherein delivering light includes delivering lighthaving different wavelengths or different patterns.
 14. The method ofclaim 9, further comprising: stimulating a second animal with a secondstimulus; and observing a resulting behavior of the second animal viaimaging both a footprint and a toe print of the second animal inresponse to the second stimulus.
 15. The method of claim 14, whereinimaging both the footprint and the toe print of the second animalincludes capturing an image of both the full footprint of the secondanimal and an image of the toe print of the second animal when thesecond animal is standing on its toes.
 16. The method of claim 15,wherein capturing the image includes detecting refracted light when thesecond animal contacts the base surface.
 17. The method of claim 14,wherein stimulating the second animal comprises stimulating the secondanimal with a second stimulus that is different from the first stimulus.18. The method of claim 1, further comprising supplying the group ofanimals for behavioral monitoring.
 19. The method of claim 18, whereinsupplying the group of animals includes supplying a group of geneticallymodified animals.
 20. The method of claim 1, wherein the base surface istransparent.
 21. The method of claim 20, wherein the base surfaceincludes a glass or plastic material.